CVE-2025-9892 in Restrict User Registration Plugin
Summary
by MITRE • 10/03/2025
The Restrict User Registration plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.0.1. This is due to missing or incorrect nonce validation on the update() function. This makes it possible for unauthenticated attackers to update the plugin's settings via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 10/03/2025
The Restrict User Registration plugin for WordPress presents a critical cross-site request forgery vulnerability that affects all versions through 1.0.1, representing a significant security flaw in the WordPress ecosystem. This vulnerability stems from inadequate nonce validation within the plugin's update() function, which serves as the primary mechanism for authenticating administrative actions. The absence of proper nonce verification creates a pathway for malicious actors to manipulate plugin configurations without authentication, fundamentally undermining the security model that WordPress relies upon for user registration controls.
The technical implementation flaw manifests in the plugin's failure to validate cryptographic nonces during administrative updates, which violates fundamental web security principles outlined in owasp top ten categories and specifically addresses cwe-352 cross-site request forgery. This vulnerability operates under the premise that an attacker can construct a malicious request that appears legitimate to the WordPress admin interface, leveraging the trust relationship between the user's browser and the target website. The attack requires social engineering elements where administrators must be tricked into clicking malicious links or visiting compromised websites, but once executed, the forged requests can modify critical plugin settings that control user registration restrictions.
The operational impact of this vulnerability extends beyond simple configuration changes, as it enables attackers to potentially disable user registration restrictions, modify access controls, or manipulate other security-related parameters within the plugin's scope. This poses significant risks to website administrators who may unknowingly grant unauthorized access to their user registration systems, potentially leading to spam registrations, unauthorized account creation, or complete bypass of intended security measures. The vulnerability particularly affects websites that rely on the plugin for controlling user access and registration flows, making it a prime target for attackers seeking to compromise WordPress sites with minimal effort.
Mitigation strategies must focus on immediate remediation through plugin updates to versions that properly implement nonce validation, while also implementing additional protective measures such as wp_nonce_field() checks in all administrative functions. Organizations should consider implementing web application firewalls that can detect and block suspicious cross-site request forgery attempts, alongside regular security audits of installed plugins to identify similar vulnerabilities. The attack pattern aligns with att&ck technique t1566 credential access through social engineering, and organizations must educate administrators about the risks of clicking untrusted links while maintaining current security patches for all WordPress components including plugins that handle sensitive configuration data.